A manual bleed valve is very easy to install. It simply works by having a small ball with a spring inside the valve which can be loosened and tightened depending on how much charge pressure you want to drive with. Just screw on the top of the valve.
However, a manual bleed valve can be a bit dangerous in the cabin as you can very quickly turn it on if you can not keep up with the car you might be driving towards.
Below you will find the manual boost controller. These types of boost controller can be placed in the engine compartment or in the cabin so you can adjust them while driving.